Separation of metals



of bismuth from ores, concentrates, com- GERALD U. GREENE, F SALT CITY,

AND REFINING COMPANY, OF NEW YORK,

ii atented Sept. i, 193i N. Y, A CORPORATION or NEW JERSEY sErABArreN or mE'rALs No Drawing.

This invention relates to the separation of metals, and more particularly to the removal pounds or various metallurgical,products.

The invention also provides for the reducf tion of the'copper content of the treated material to a sufiiciently low value to render the material suitable for certain metallurgical purposes.

The invention provides for roasting the material contaimng b'lSlllUtll and copper 1n the presence of a reagent which 1s capable of uniting with the bismuth and rendering the same volatilizable and of rendering the copper soluble in acid leaching solutions. The residue. after leaching, is low in bismuth and copper and may be used in various arts. such for example, as the manufacture of red lead or corroding lead.

The invention further consists in the new and novel features of operation and the new and original arrangements and combinations of steps in the process hereinafter described and more particularly set forth in the claims.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto. the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following description in which a particular commercial embodiment thereof is disclosed.

' It will be understood however, that the processes and the steps thereof may be modified in various respects withoutdeparting from the broad spirit and scope of the invention. Inthe following description and in the claims the various steps in the process and the details comprising the invention will be identified by specific names for convenience but they are intended to be as generic in their application as the art will permit.

The invention provides for the roasting of the bismuth and copper bearing materials in the presence of a chlorine compound and at a sufiiciently high temperature to form chlorides of bismuth and copper. The bismuth chlorides are volatilized at the roasting temperature and may be recovered in any Application filed August 8, 1929. Serial No. 384,474.

suitable apparatus, such as a bag-house.

Any bismuth chlorides remalning in the charge, together with substantially the entire content of copper chlorides, are soluble in'certaln acids and may be removed byleaching the charge therein. The residue is thus freed from these elements and may be utilized as desired in thearts. I

The process more particularly comprises mixing ores, concentrates, compounds or other metallurgical products and particularly bismuth bearing materials with a small percentage of sodium chloride, after which they are roasted in any suitable furnace. The temperature of the roastor the'chloridi- Zation may be varied depending upon the percentage of lead. A. temperature of some 450 to 600 C. has'been found suitable for this purpose. ride required is also determined by the composition of the material and has been found to vary from 17c to. 5%.

The bismuth, volatilized as bismuth chloride, is recovered in a suitable bag-house and the residue is leached, if desired, in dilute sulphuric acid which removes the remainder of the bismuth and substantially the entire copper content.

As a specific example of the process a concentrate containing 2.52% bismuth, 38.1% iron, 3.-t5% tin, 1.17% zinc and 3% lead was treated for one hour at a temperature of 600 C. with 2% of sodium chloride. It was found that 99.7% volatilized.

As a further example, a lead concentrate containing 51.5% lead, and .1876 bismuth was treated for one hour at a temperature of 420 C. with 3% sodium chloride. This resulted in the volatilization of 77.6% of the bismuth;

A sample of smelter flue dust containing 53% lead and .4570 bismuthwas treated for thirty minutes with 5% sodium chloride at a temperature of 455 C. In this case 91.5% 0f the bismuth was volatilized. It was found UTAH, ASSIGNQR To AMERICAN SMELTING The amount of sodium chlofound that 98.1%

these conditions the bismuth was volatilized-- PI' CQSS of treating lead bearing matewithin one hour.

In carrying on the process as above, it was of the copper is rendered 5 soluble in sulphuric acid.

It is to be noted therefore that in processes requiring the complete elimination of copper the product.may be used to advantage since the amount of copper which must be subsequently removed is reduced to a small the bismuth has After chloridization and leaching been reduced'to 037% and the copper to'slightly over 0.1%. The co per could of course be, recovered from the acid solution in any well lmown manner.

The lead is not volatilized to any appreciable extent during the salt .roast provided the sulphur content of the charge is not excessive.

f a large amount of sulphur in the sulphide form is present, the oxidization of the sulphur during the roasting operation may interfere with the temperature control and prevent proper to be noted that bismuth sulphate decomposes more readily than lead sulphate and at an appreciably lower temperature, whereas bismuth chloride has a slightly higher formation temperature than lead chloride. For

value.

this reason the bismuth chloride is formed in preference to lead chloride during thesalt roast, thereby enabling the bismuth to be largely volatilized and removed without substantial loss of lead.

In the above described process the bismuth content of the material may be so treated that the product is suitable for corrod'm lead. For this purpose the bismuth is pre erably reduced to 02%. In case it is desired to use the product for the manufacture of red lead, the elimination of the copper is a articularly important feature, as it woul be necessary to remove this element by the use of additional reagents prior to manufacture of red lead. The process may be cheaply carried on, particu arly in localities wh'ere salt may be easily obtained. It is to be understood that calcium chloride may be utilized instead of sodium chloride when that sub stance can be convenientl obtained.

Although certain novel aatures of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the several steps of the process and in its'operation may be made by those skilled in the art without departing from the spirit of the invention. 1 at is claimed is: l

1. Process of treating lead bearing materials for the elmination of bismuth which comprises mixing said material with a small percentage of a chlorine compound and roasting the mixture at a temperature at which the bismuth is volatilized as a chloride without appreciable loss of lead.

regulation thereof. It is also temperature of 450 to 600 of time-sufficient to substantially completely mixture at a temperature of 450 to 600 C.

whereby the bismuth is volatilized as a chloride without an appreciable loss of lead.

4. Process of treating leadbea-ring materials for the elimination of bismuth and copper which comprises chloridizing said materials at a temperature of 450 to 600 C. for a period of time sufficient to substantially completely volatilize the bismuth as achlo ride, collecting and recovering said bismuth, leaching the material in a dilute acid solution whereby the copper and the remainder of the bismuth are largely removed and recovering the copper from the acid leach.

5. Process of treating lead bearing materials for the elimination of bismuth and copper which comprises chloridizing said materials at a temperature of 450 to 600 C. for a period of time suflicient to substantially completely volatilize the bismuth as a chloride, collecting and recovering said bismuth, leaching the material in a sulphuric acid solution whereby the copper and the remainder of the bismuth are largely removed and recovering the copper from the acid leach.

6. Processof treating lead bearing materials for the elimination of bismuth which comprises chloridizing said materials at a C. for a period volatilize the bismuth as a chloride, collecting and recovering said bismuth, leaching the material in a dilute acid solution whereby the remainder of the bismuth is largely removed.

7. Process of treatin lead bearing materials for the elimination of bismuth and copper which comprises chloridizing said materials at a temperature of 450 to 600 C. for a period of time sufficient to substantially completely volatilize the bismuth as a chloride, and leaching the material in a dilute acid solution whereby-the copper and the re 1 mainder of the bismuth are largely removed In testimony whereof I have hereunto set my hand. GERALD U. GREENE. 

